Atomic and molecular data: data organization in A+M databases and their use for stellar spectroscopy
An important role of atomic parameters and cross-sections in stellar spectroscopic analysis is demonstrated on different astrophysical applications: determination of fundamental stellar parameters and chemical composition, Galaxy chemical evolution, exoplanet formation. A range of the required accuracy in laboratory and theoretical data for these studies is discussed. The feedback of the high-precision modern astronomical spectroscopy to the improvement of the laboratory data is underlined. Finally, I review shortly the main atomic and molecular databases containing atomic parameters and cross-sections needed for detailed analysis of high resolution, high signal-to-noise ratio stellar spectra.